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Re: [bluetooth-dev] solving a broadcast problem through bluetooth



Hi,
Thanks for your reply, Yes, u r right that a slave cannot broadcast, but a 
Master can, What happens if they want to form a new piconet and sends the 
*query* packet, since there is no prior notification in broadcasting to 
other nodes, if the other node is also sending a *query* packets or two or 
more nodes reply to that *query* packet at the same time, their packets will 
collide *at the reciever*. Although the solution given for that, *the Master 
won't reply and those nodes will wait for random amount of time and resend 
the packet again.*

Hope that would clear, What exactly I wanna know, since I am not fully 
convinced the *random amount of time waitage * stuff before resending the 
packet. It doesnt give you the gurantee that packet won't collide again.
I am interested in knowing that, are there any control signals for notifying 
other nodes that *Hey Iam sending a broadcast *query packet* and nobody 
dares to send or recieve any packet during this packet time*

Please let me know

Thanks in advance

Hashir Kidwai



>From: Gordon McNutt <gmcnutt@xxxxxxx.com>
>To: ping kidwai <monuser@xxxxxxx.com>
>CC: bluetooth-dev@xxxxxxx.com
>Subject: Re: [bluetooth-dev] solving a broadcast problem through bluetooth
>Date: Tue, 30 Jan 2001 03:42:31 -0700
>
>ping kidwai wrote:
>
> >   Hi, My name is Hashir Kidwai. I am currently focusing on a Topic of
> > Ad-Networks and would like to know that whether that problem or topic 
>can be
> > solved via BlueTooth or not. The Topic is: One node transmits a 
>broadcast
> > message and *all* its neighbors receive it successfully. This means that
> > none of its neighbors should be transmitting or receiving other messages
> > during this time period. In MACA the receiver is told of an upcoming
> > transmission by means of the RTS/CTS exchange. However, how would this 
>work
> > if there are multiple simultaneous receivers for one transmission?
> >
> > _________________________________________________________________
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> > To unsubscribe from this list: send the line "unsubscribe bluetooth-dev" 
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>
>Hi Hashir,
>
>In Bluetooth, the answer depends on whether or not the node in question is 
>a
>master or a slave. If the node is a master, then it can broadcast to all 
>slaves
>on its piconet. But if it is a slave, then it cannot broadcast -- it can 
>only
>talk to its master.
>
>Transmission collision on Bluetooth is avoided with the following scheme. 
>Legal
>transmission times on a piconet are divided into slots. Some slots only the
>master can transmit, and all slaves listen for packets addressed to them. 
>Other
>slots only one slave can transmit, and the master listens. A slave knows 
>that
>it can transmit, and not collide with another slave, if and only if the 
>master
>addressed it in the previous master transmission slot. This scheme is 
>covered
>in the baseband protocol portion of the core spec.
>
>--gmcnutt
>

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